The large, twee virtual "stickers" for sale in the newly released Path 3.0 for iOS look like something out of an East Asian messaging app, such as KakaoTalk or WeChat. And, just like in these East Asian apps, the $1.99 sticker packs open up a new revenue stream for Path, whose new version also includes a private messaging feature.

So far, the stickers are a much better experiment in monetization for the private social networking app than the $0.99 premium photo filters it began offering two years ago: Stickers generated more revenue in their first 24 hours on sale than Path's photo filters earned in a year, cofounder Dave Morin revealed during a one-on-one discussion with Vanity Fair editor Krista Smith at South By Southwest.

Morin said although some users might not think filters are worth paying for—especially when they're free on Instagram and Twitter—"the uniqueness of stickers offers a different value proposition."

Morin, who is known for his meticulous attention to detail and design, says the emoji-inspired stickers are a way for people to express themselves with a single tap, yet in a way that can often feel "more authentic" than a plain text message. They're part of an attempt to address a basic challenge Morin sees with social software: "It has to be more human."

To that effect, the stickers went through hundreds of iterations before 3.0 launched. For example, Morin and his team initially thought users would enjoy a food-themed pack featuring sushi or hamburger stickers. "It turns out people don't like using static objects to communicate," he says. "They like using characters." After a few trips back to the drawing board, they came up with the "Nom Nom Parade" pack—featuring animated comestibles such as a walking pizza—which is now the third-most popular set.

Morin says Path will release new sticker packs every week, reiterating his plans for Path's long-term business model to revolve around the selling of virtual goods, rather than advertising.